1. Field of the Invention
The present invention relates, e.g., to a digital copying machine for copying a portion outside an original as a blank.
2. Description of the Related Art
In recent years, a digital copying machine utilizing the digital technique has been developed and put into practical use as a copying machine. More specifically, an image from the original is read by a CCD (charge-coupled device) line sensor, and a signal from the line sensor is processed by quantization.
When a thick original, e.g., a book, is to be copied by using such a digital copying machine, since a platen cover for pressing the original can be closed only halfway, a portion of the platen cover corresponding to the outside of the original floats from the original table and is copied in black. For example, when originals "AAA", "BBB", and "CCC", and a small area such as dust exist on the original table, portions other than the originals "AAA", "BBB", and "CCC", and the small area such as dust are copied in black.
A copying machine has been developed which performs correction in order to whiten an area other than a original. In this copying machine, however, if a plurality of originals "AAA" and "BBB" exist in the main scanning direction, both a portion between the originals "AAA" and "BBB" in the main scanning direction and a portion between a small area and the original "CCC" in the main scanning direction are not judged as portions outside the original. Thus, the portions between the plurality of originals or a portion between the small area and the original in the main scanning direction is treated as a portion where the original exists, and such a portion is copied in black.